If you don't do it right the oil gets in the inlet causing various problems such as lean running & det. The idea is to catch that oil in a can so it's not filling up your intercooler etc. It can then be disposed off or returned to sump depending on set up. If you aren't catching it in a can then it's either in your intercooler etc or all over your engine from your breather vents. 3 port works best as each breather has it's own port into the can, but other set ups can work. Hope this helps.

 

+1

 

The original system is plumbed to go back into the inlet anyway so surely that would casue lean running?

I have mine VTA with little air filters on top and don't get any issues with oil leaking, i'm sure if i was doing a lot more mileage it may be a problem but for now it's fine.

 

done 100 miles with the temp set up (three bottles) and all is well, also read somewhere that the version 8 sti engines do breathe a tad heavy. just ordered new tank fingers crossed will be here for weekend

 

Correct the original goes to the inlet & most tuners will tell you when fitting a catch tank it's best to blank the PCV for reasons stated in previous post. VTA can work but only if the PCV is blanked off, & then the oil which would have gone in the tank will be venting out of the breathers making a lovely mess. If you still have a PCV your crank case still vents into your inlet manifold. If you are running standard power it's not such an issue .

 

not quite standard

 

Only when off boost, so I can't see why keeping the pcv is a problem

 

I'm only speaking from my own experience,having previously had 2 set ups which were not correct. After my last set up which did not catch a single drop of oil & left oil in my intercooler, I decided to do my homework. After speaking to several people who know more than me I came up with my set up which does catch all the oil & leaves nothing in the intercooler. Andy Forrests website is well worth a read & gives info on this.
If you are happy with your set up who am I to argue,but the only gauge of how well it works is to check the intercooler for oil & mine is bone dry,not a drop.

 

Nice engine bay. Let us know how you get on with the new tank. Good Luck, Richard.

 

I'd always say keeping the PCV is better on a road car. It removes moisture from the crankcase, and stops water in suspension messing up your oil.
If it's working properly, it isn't an issue with a turbo. We tend to feed the breather pipes into a catch tank if required, then feed the catch tank breather back into the inlet. The tank holds any oil, and the intake keeps a slight negative pressure in the sump, which helps prevent oil passing the turbine ring seal.
With really high boost turbos, it's hard to stop breather gases being an issue, so then we go for sealed catch tank systems, returning oil back into the sump.

 

thanks
early signs are positive just want to make sure everything perfect before the final map

 

Alan,
Mine boosts to 1.9 Bar, would you consider this high boost? Also it only catches oil with the PCV blancked. I don't return to sump as Iv heard it can condensate the oil is this correct? My tank vents to atmosphere but I'm considering piping it back into the turbo inlet pipe,is this advisable & can it cause any issues?
Sorry for so many questions, but there are so many conflicting opinions on catch tank set ups.
Thanks, Richard.

 

I wasn't knocking your setup at all mate, sweet looking bay It was a general genuine question about why the need to remove the pcv when it is not in use when on boost. What is the benefit?
I currently have a 3 port, retaining the pcv and venting to atmosphere but doesn't return to sump. It collects no oil at all when driving on the road but 15mins of track action sees it half full! So I am in the process of making it return to sump.

 

There are differing opinions on catch tank set up. The idea behind binning the PCV is to keep ALL the oil out of the inlet. Your set up may work with PCV but mine did not & Iv heard other people say the same.
If you are catching oil & there is none in the intercooler & inlet then it's working. However I'd check the intercooler now & then & if it gets oily bin the valve. On track return to sump is best but on the road it puts condensation into the oil. Perhaps think about a set up which can easily be changed for the track.
I don't think there is a right & wrong way to fit a catch tank, just the one that works best on your car. Most tuners seem to have slightly differing set ups.

 

Blanking the PCV will not stop oil getting into your IC, seeing as the PCV is in the inlet manifold which is after the IC, the only way of stopping the oil in there is to divert the pipes that normally go in to the inlet before the turbo.

 

As most of the oil suspended in the Breather gases comes from the crank case breather which is then recuirculated into the inlet which flows through the intercooler removing the PCV will help this issue. On a modified set up where the pipes go only to a catch tank it will still help by not letting the oil into the inlet manifold which potentially could cause lean mixture.

 

Yeah i have seen a lot of different ways of setting it up and everyone has an opinion on the best way.
I kept the pcv for simplicity more than anything.
I did consider a tap to switch off the return to sump for road driving but i don't know if its worth the effort to setup as mine isn't a daily driver.
Like you said all you can do is go with what works best for you.

 

Hi Alan ,

Is it essential to have a feed back to the inlet for the negative pressure?

Barry